1. Field of the Invention
The invention relates to locking telescoping members that are often used to support or level a given object or device.
2. Background Art
The prior art teaches a myriad of extendable support members or legs for a variety of objects and devices, by which each are provided a limited ability to accommodate an uneven or inclined supporting surface. Often, the object or device is a portable device that preferably accommodates a wide variety of such supporting surfaces through use of one or more such extendable support members. Generally, known extendable support members include a pair of coaxial, telescoped members, wherein one member is selectively translated relative to the other in order to achieve an extended condition providing the support with a desired overall length, perhaps with the aid of a screw drive or a ratchet-tensioned pulley system. The support is thereafter maintained in an extended condition with a locking mechanism that may include a transverse locking pin, a rotatable chuck or locking collar, or a ratchet mechanism. Upon release of the locking mechanism, the one member may be moved in the opposite direction, perhaps with the aid of a return spring, to thereby return the support to a retracted condition.
For purposes of illustration, in the context of an adjustable-length kickstand for a motorcycle, the relative translation of the one member relative to the other member is often achieved with the aid of gravity, with the one member sliding relative to the other member once both an associated stowage lock has been released and the kickstand has been pivoted from a generally horizontal stowage position to a generally vertical position, as taught in U.S. Pat. No. 4,432,562. Alternatively, the one member is manually extended relative to the other member, either by hand or using the operator""s foot, perhaps as further resisted by a return spring.
Once adjusted to the desired overall length, the members of the kickstand are locked relative to one another, for example, by insertion of a locking pin through a pair of aligned holes formed in the members as in U.S. Pat. No. 5,388,848, or by tightening an encompassing collar so as to generate an interference between the two members as in U.S. Pat. No. 4,169,687, or by tightening a set screw as in U.S. Pat. No. 4,986,557. Another approach is to employ a ratchet mechanism as in U.S. Pat. No. 4,432,562. Yet another approach is to include a cooperating pin and slot mechanism as taught in U.S. Pat. No. 4,580,804, in which the extended member is rotated about its longitudinal axis such that a projecting pin on the extended member is urged into one of several longitudinally-spaced canted slots.
When the kickstand is to be longitudinally collapsed, the locking mechanism is manually deactivated or decoupled, as by removing the locking pin, or turning the chuck or collar, or tensioning a release cable for the ratchet mechanism of U.S. Pat. No. 4,432,562, or counter-rotating the one member to disengage the cooperating pin and slot mechanism of U.S. Pat. No. 4,580,804, whereupon the one member may be moved back to a retracted position relative to the other member. Unfortunately, such manual deactivation or decoupling of the locking mechanism and, particularly, those requiring the relative rotation of a locking mechanism or one of the members themselves, can be difficult because the motorcycle operator must simultaneously balance the weight of the motorcycle.
Accordingly, what is needed is an adjustable telescoping support member that is simply and readily extended and automatically locked when its attitude is changed from a first orientation to a second, orientation relative to plumb and, further, whose locking mechanism is readily operated to decouple the support""s telescoping members without any external manipulation once the support is returned to, or moved through, the first orientation.
Under the invention, an extendable support member includes a first elongate member defining a longitudinal bore along a longitudinal axis, wherein an inner surface of the bore includes a recess; and a second elongate member adapted to be received in the longitudinal bore of the first member, wherein an outer surface of the second member includes a recess that is canted relative to the longitudinal axis.
The support member further includes at least one gravity-responsive locking element, preferably carried within a respective recess of one of the inner and outer members, wherein the locking element is movable within the recess under the influence of gravity from a first engaged position coupling the first member to the second member, to a second position that permits relative movement of the first and second members, as the first and second members are moved from a first relative attitude to a second relative attitude by pivoting the first member from an operative orientation to a stowage orientation. In a preferred embodiment, the locking element includes an element, such a hardened steel ball, that rolls within the recess of the second member. The locking element similarly preferably moves in response to gravity from the second position toward the first position as the first and second members are moved back into the first relative attitude, e.g., into the operative orientation, to thereby provide automatic xe2x80x9clockingxe2x80x9d of the extended second member when in the operative orientation.
In accordance with another feature of the invention, the locking element can include one or more struts, preferably carried within respective recesses of one of the members, that pivots between a first position that permits relative movement of the members and a second position in which the ends of the strut respectively engage the recesses of the inner and outer member to thereby lock the inner member relative to the outer member. While the strut can be formed such that the strut itself responds to gravity in accordance with the invention to thereby the respective ends into engagement with the members, the invention contemplates use of an additional gravity-responsive element, such as the rolling element described above, to assist in so biasing each strut. To facilitate decoupling of the strut when the support member is in the stowage orientation, and to further ensure that the back end of the strut will not pop up to prevent extension of the second member when in the operative orientation, the strut preferably includes a pair of laterally-extending arms proximate to a second end opposite the first end, and wherein the inner surface of the first member overlies the arms of the strut to maintain the second end of the strut in the recess of the second member.
In accordance with another feature of the invention, the support member further includes a spring urging the second member toward a retracted position relative to the first member. The spring ensures the continued locking of the extended second member within the first member until the first member is moved to the stowage orientation and the second member is slightly extended to thereby permit gravity to urge the locking element back toward its first, decoupled position. In a preferred embodiment, the spring is disposed within the longitudinal bore of the first member.
Other advantages, features, and benefits of the invention will be readily apparent from the following detailed description of a preferred embodiment, when taken in connection with the accompanying Drawings.